Over the years various different materials have been used to install water service lines, also referred to as water mains even though that is technically incorrect. What follows is a brief tutorial about the different water main pipe material that has used for water supply lines over the years. Most water lines for private properties are not actually pipes, but rather tubing. Learn about the particular characteristics of each material. Some water service line material such as lead and galvanized pipe are no longer legal to install or to repair in certain areas, such as in New York City. Also note that plastic as a water service line material has never been legal in NYC for use; therefore it is not explained in this tutorial.
Lead – Lead Water Service Lines
Lead is not technically a water main pipe material, as it is not considered a pipe, and was solely for service lines. Lead has not been an approved material for a water main service in over 60 years. Lead in the drinking supply does not occur naturally; it does not come from rivers, reservoirs, etc. If lead is present in a house supply system it typically emanates from the water main distribution system or house plumbing.
There are various services that test for lead inexpensively. If a house is serviced by a lead water main it is strongly suggested that before using water the tap be run for 15 to 30 seconds when it has not been run for 6 hours or so. This precaution will help eliminate the possibility of ingesting lead which could lead to lead poisoning.
There are a few ways to determine if a water main service line is lead. Lead is characterized by a silver color, is malleable, and has a round shaped “wipe joint” just before the main control valve (refer to photo and video). Wiped joints had to be used because lead cannot be threaded like a pipe can.
The NYC DEP code does not permit the repair of an existing lead water service line. If repair work is needed on a lead service line, by law it must be fully replaced. In addition, once an existing lead water service is moved in any manner tiny hairline cracks are made. These small cracks, which may not even be visible, will form into a leak typically within 18 months or less.
Galvanized – Galvanized Water Main Pipe Material
Galvanized pipe, when used for water main service lines, are primarily found in only certain areas of NYC. Mostly residents with galvanized lines were previously serviced by a private water supply company such as Jamaica Water (JWP).
Galvanized is a water main pipe material that is actually a pipe. A pipe has the characteristic of being able to be threaded on each end, and is rigid. Galvanized pipe is not legal in NYC as a material for a water service.
Galvanized piping reacts to contact with water or moisture, and corrodes on both the outside and inside of the piping (refer to photo and video). It is similar to a clogged artery in a person – only instead of a heart attack you get a flood! It is strongly suggested that any existing galvanized water service be replaced immediately with better materials, as when they leak the service typically ruptures.
The NYC plumbing code does not permit repairs on existing galvanized water main service lines. In addition repairing an existing galvanized water service would be a repair with little integrity. The same applies for an existing lead water service line.
It is easy to determine if a water service is galvanized as it is the only water service material that is magnetic. Simply place any magnet on the water service, if it sticks the service is galvanized.
Typically when water is turned on in a house with galvanized piping the initial water will be rust colored or contain rust. Impurities in levels such as these are not typically found in copper water services
Copper – K Copper Water Service Line Tubing
K type copper is the material that the vast majority of water services lines are presently installed with in NYC. K copper is actually water tubing, not technically a water main pipe material. In addition most existing water services are K copper. K copper tubing (not pipe) is used for water services up to 2″ in size.
K copper water services are characterized by flare fittings at the end of the tubing (refer to photos below) and the fact that they are malleable and able to bend without damaging the service line.
The fact the copper water tubing is malleable is a key factor in why they last so long. This enables copper tubing to withstand ground shifting better than other approved plumbing materials. K copper water services typically have a lifespan in excess of 50 years. [Read more about copper water service lines]
Brass – Brass Water Main Service Lines
Brass pipe is threaded at each and is connected by the use of brass couplings. Brass is classified as a water main pipe material, as it is actually pipe. Brass is generally used solely for a 2 1/2″ water service line in New York City. Therefore it is a material that is used infrequently. Another factor limiting the use of Brass is that it is extremely expensive compared to other approved water supply line materials.
Brass is a metal composed primarily of copper and zinc. Copper is the main component and brass is usually classified as a copper alloy material. Brass is stronger and harder than copper, but not as strong or as hard as steel. Brass water service lines have a life expectancy in excess of 50 years. Unlike copper water tubing, brass is not malleable. But brass pipe does have a thicker wall thickness than K copper water tubing.
Brass is not a magnetic material; so to test whether a water service is galvanized or brass a magnet can be used. Galvanized is a magnetic material. Brass and galvanized pipe can appear similar to the naked eye, but have very different characteristics and properties. Both brass and galvanized are threaded pipe, however unlike galvanized pipe brass is a legal material in NYC and has a much longer life expectancy.
Ductile Iron Pipe – Ductile Iron Water Main Lines
Ductile Iron pipe is a cement lined material used for water services larger than 2″ in diameter. Typically used for fire sprinkler mains, or for buildings such as large apartment or office buildings.
Ductile Iron pipe is the same water main pipe material that NYC uses for its distribution system. Once installed, ductile iron pipe lasts for many decades. Our of all the materials used, Ductile iron may be the most durable water main pipe material, or tubing material, approved for use in NYC.
Ductile iron pipe is unique in that it is put together using either push-on joints, or mechanical joint retainer glands with set screws. That means it is typically not threaded like typical pipe, nor flared like copper tubing. Ductile Iron Mechanical Joint pipe contains no lead whatsoever (refer to photos).
In some specific instances, such as unstable ground conditions, ductile iron pipe is used for house sewer installations as well as for a water main, or water service line. Previous to the advent of Ductile Iron pipe, cast iron was utilized for these same installations. Cement lines Ductile Iron pipe is far superior and longer lasting material than cast iron, or extra heavy cast iron.